Bidirectional flow catheter

ABSTRACT

Disclosed herein is a bidirectional intravascular cannula, or catheter, that is configured to provide and return blood in a patient bidirectionally. The bidirectional intravascular cannula is configured to reduce or obviate the need for a second cannula, such as currently available unidirectional cannulae, to be placed in a second or opposite direction of flow. Users would include cardiac surgeons, intensivists, vascular surgeons, ER doctors, IR doctors and cardiologist who use peripheral cannulation for ECLS or cardiopulmonary bypass. The cannula allows continued flow to a patient&#39;s limb even with the cannula proximally in the vessel. The cannula further allows larger size cannula to be placed without the need for additional distal catheter placement.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/754,382 titled “BIDIRECTIONAL FLOW CATHETER,” filed Apr. 8, 20202,now. U.S. Pat. No. 11,364,333, which is a national stage entry ofInternational Patent Application No. PCT/US2018/055160, titled“BIDIRECTIONAL FLOW CATHETER,” filed Oct. 10, 2018, which is based uponand claims the benefit of U.S. Provisional Application No. 62/570,148titled “BIDIRECTIONAL FLOW CATHETER,” filed with the United StatesPatent & Trademark Office on Oct. 10, 2017, the specification of whichis incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of medical devices,and more particularly to cannulae and systems using cannulae forperipheral extra corporeal life support (ECLS), including cardiac orpulmonary indication.

BACKGROUND

Blood circulation in a person's heart and lungs is described here toprovide a better understanding of certain aspects of embodiments of theinvention as set forth herein. Blood travels in a patient's body to apatient's heart from the upper part of the body through the superiorvena cava (SVC), and from the lower part of the body through theinferior vena cava (IVC), into the right atrium. Blood moves bothpassively and actively through the right atrium and tricuspid valve intothe right ventricle, which in turn contracts to force blood through thepulmonary valve and into the pulmonary artery. The pulmonary arterydirects blood to the lungs, where the blood is oxygenated.

After the blood is oxygenated in the lungs, it returns to the heartthrough the pulmonary vein and into the left atrium. The left atriumboth passively and actively allows blood through the mitral valve andinto the left ventricle. The left ventricle then pumps the blood intothe aorta, which then distributes the blood to the rest of the body.Blood flow in a patient's body, and particularly the oxygen carried bythat person's blood as it courses through their body, is adverselyaffected by heart failure and lung disease, both of which are pervasivekillers.

Heart disease is a significant killer in the U.S., responsible forapproximately 1 in 3 deaths (American Heart Association). Approximately800,000 deaths annually are attributed to heart disease, despitebillions in expenditures to fight the disease. When the heart fails topump an adequate amount of blood, extracorporeal life support (ECLS) canbe utilized to bypass the heart and lungs and pump oxygenated blood tothe body.

In clinical practice, ECLS (and other practices including extracorporealmembrane oxygenation (“ECMO”)) requires a cannula, which is a medicaltube inserted into the body for drainage and/or infusion of fluids, suchas blood in the case of ECLS. The major problems of available cannulaefor ECLS include: (1) cannulation and insertion of cannulae with largerdiameters causing extra trauma to patients; (2) the cannula placed in anartery can obstruct distal blood flow due to its large diameter; and (3)damage to adjacent tissue during placement and/or removal.

Thus, currently available arterial cannulae used for cardiopulmonarybypass during surgery and veno-arterial ECLS can obstruct distal flow tothe limb in which the cannula is inserted (e.g., the lower leg withfemoral cannulation). This can lead to devastating ischemic injury ofthat limb. Previous efforts to alleviate that risk having includedplacement of a smaller than desirable sized cannula that will notobstruct the vessel proximally to the point of insertion, or theplacement of an additional catheter distally to the point of insertionof the cannula to provide flow to the distal portion of the limb.

Further efforts have been made to provide for distal perfusion,including efforts to provide cannulae with a secondary port positionedproximally to the distal end of the cannula, which secondary port isintended to allow blood to flow into the artery in a direction oppositethe flow direction from the distal end of the cannula. For example, U.S.Pat. Nos. 5,171,218 and 5,330,433 to Fonger et al. are directed to anarterial cannula having a diverting side hole positioned proximally onthe cannula from the distal end, with barbs on the exterior of thecannula on opposite sides of the diverting side hole. Further, U.S. Pat.No. 8,795,253 and U.S. Patent Application Pub. No. 2014/0330250 toMoshinsky et al. disclose a cannula having a first aperture at a distalend and a second aperture positioned proximally to the distal end, witha protuberance at the second aperture that engages the wall of thepatient's blood vessel to prevent its collapse during use. However, suchprior efforts have shortcomings, in that they typically exhibit sharpsurfaces or facing edges that make it difficult for an operator to placeand remove the cannula from the patient's artery, and increase risk ofinjury to the patient during placement and/or removal. Moreover, suchpreviously known configurations are prone to movement with respect tothe patient's artery as the patient moves, risking dislodgement,bleeding, and general injury to the patient.

Accordingly, there remains a need in the art for a device, systems, andmethods that will reduce the harm associated with cannulae used duringECLS, that will minimize the risk of blood flow obstruction and damageto the patient's tissue, and that particularly will offer a minimallyinvasive, efficient, and simple percutaneous cannula for use with ECLSand cardiopulmonary bypass procedures.

SUMMARY OF THE INVENTION

Disclosed herein are devices and methods configured to address one ormore of the above described disadvantages of the prior art. However,achieving the above purposes and/or benefits is not a necessary featureto each of the exemplary embodiments, and the claims herein may recitesubject matter that does not achieve the above stated purposes.

In accordance with certain aspects of an embodiment of the invention, abidirectional intravascular cannula, or catheter, is provided that isconfigured to provide and return blood bidirectionally. For example, thecannula can provide blood to a patient's blood vessel, such as to apatient's arteries, without causing significant blockage that can reduceblood flow to the patient's limbs, even if the cannula is placedproximally in the blood vessel. Thus, the bidirectional intravascularcannula reduces or obviates the need for a second or distal cannula tobe placed in a second or opposite direction of flow of currentlyavailable unidirectional cannulae. This bidirectional intravascularcannula provides bidirectional flow via a biocompatible reverse flowport. The cannula can be used, by way of non-limiting example, bycardiac surgeons, intensivists, vascular surgeons, ER doctors, IRdoctors and cardiologists for peripheral cannulation for ECLS orcardiopulmonary bypass during heart surgery.

In accordance with further aspects of an embodiment of the invention, abidirectional flow catheter system is provided, comprising: a cannulahaving a distal end and a proximal end opposite the distal end; aforward flow port at the distal end of the cannula, the forward flowport configured to direct fluid from the cannula in a first direction; areverse flow port positioned proximally from the distal end of thecannula, the reverse flow port configured to direct fluid from thecannula in a second direction; and a cap positioned on an exterior ofthe cannula and extending over the reverse flow port.

In accordance with still further aspects of an embodiment of theinvention, a bidirectional flow catheter system is provided, comprising:a cannula having a forward flow port at a distal end thereof and areverse flow port positioned proximally to the distal end; and anobdurator having an outer diameter approximately equal to an interiordiameter of the cannula at the distal end of the cannula, the obduratorhaving a channel in a side wall of the obdurator, the channel having adistal channel end that is proximal to a distal end of the obdurator anda proximal end adjacent to a widened-diameter portion of the cannula;wherein the channel is positioned on the obdurator to align with thereverse flow port when the obdurator is fully inserted into the cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a side view of a bidirectional flow catheter in a blood vesselof a patient in accordance with certain aspects of an embodiment of theinvention.

FIG. 1A is a close-up side view of a reverse flow port on thebidirectional flow catheter of FIG. 1.

FIG. 2 is a side view of the bidirectional flow catheter of FIG. 1 in acommon femoral artery.

FIG. 3 is a cross-sectional view of the bidirectional flow catheter ofFIG. 1 in a blood vessel and showing a blood flow direction.

FIG. 4 is a close-up, cross-section view of a reverse flow port on thebidirectional flow catheter of FIG. 1 and showing a blood flowdirection.

FIG. 5 is a top view of the reverse flow port on the bidirectional flowcatheter of FIG. 1.

FIG. 6 is a top view of the reverse flow port on the bidirectional flowcatheter of FIG. 1 and showing cross-section lines.

FIG. 6A is a lateral cross-sectional view of the bidirectional flowcatheter of FIG. 1 along section line A-A of FIG. 6.

FIG. 6B is a lateral cross-sectional view of the bidirectional flowcatheter of FIG. 1 along section line B-B of FIG. 6.

FIG. 6C is a lateral cross-sectional view of the bidirectional flowcatheter of FIG. 1 along section line C-C of FIG. 6.

FIG. 7 is a side view of the bidirectional flow catheter of FIG. 1.

FIG. 8 is a top view of the bidirectional flow catheter of FIG. 1.

FIG. 9 is a close-up perspective view of the reverse flow port on thebidirectional flow catheter of FIG. 1.

FIG. 10A is a close-up, side perspective cross-sectional view of thebidirectional flow catheter of FIG. 1 in a blood vessel at the locationof the reverse flow port.

FIG. 10B is close-up, front perspective cross-sectional view of thebidirectional flow catheter of FIG. 1 in a blood vessel at the locationof the reverse flow port.

FIG. 11 is a close-up, side view of the bidirectional flow catheter ofFIG. 1 showing exemplary dimensions of portions of the reverse flowport.

FIG. 12 is a close-up, front view of the reverse flow port on thebidirectional flow catheter of FIG. 1 showing exemplary dimensions ofportions of the reverse flow port.

FIG. 13 is a close-up, side perspective view of the bidirectional flowcatheter of FIG. 1 with a cap over the aperture of the reverse flow portshown in phantom.

FIG. 14 is a close-up, top view of the aperture of the reverse flow portshowing exemplary dimensions of the aperture.

FIG. 15 is a close-up, side view of the cap of the reverse flow portshowing exemplary dimensions of the cap.

FIG. 16 is a close-up, top view of the cap of the reverse flow port.

FIG. 17 is a top, side perspective, horizontal cross-sectional view ofthe bidirectional flow catheter of FIG. 1 and showing a flow direction.

FIG. 18 is a close-up, top horizontal cross-sectional view of thebidirectional flow catheter of FIG. 1 showing a flow direction from thelumen of the cannula into the reverse flow port.

FIG. 19 is a top, side perspective, vertical cross-sectional view of thebidirectional flow catheter of FIG. 1 and showing a flow direction.

FIG. 20 is a side view of the bidirectional flow catheter of FIG. 1 withan obdurator full inserted into the catheter.

FIG. 21 is a bottom view of the obdurator of FIG. 20.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description is provided to gain a comprehensiveunderstanding of the methods, apparatuses and/or systems describedherein. Various changes, modifications, and equivalents of the systems,apparatuses and/or methods described herein will suggest themselves tothose of ordinary skill in the art. Descriptions of well-known functionsand structures are omitted to enhance clarity and conciseness.

Hereinafter, an apparatus and method for enabling bidirectional flowduring extracorporeal life support (ECLS) or cardiopulmonary bypass isdisclosed. Embodiments of the invention may, however, be configured inmany different forms for various other procedures and should not beconstrued as limited to the exemplary embodiments set forth herein.Rather, these exemplary embodiments are provided so that this disclosureis thorough, and will fully convey the scope of the invention to thoseskilled in the art.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals are understood to referto the same elements, features, and structures. The relative size anddepiction of these elements may be exaggerated for clarity.

It will be understood that for the purposes of this disclosure, “atleast one of X, Y, and Z” can be construed as X only, Y only, Z only, orany combination of two or more items X, Y, and Z (e.g., XYZ, XZ, XYY,YZ, ZZ). Further, it will be understood that when an element is referredto as being “connected to” another element, it can be directly connectedto the other element, or intervening elements may be present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. Furthermore, the use of the terms a, an, etc. doesnot denote a limitation of quantity, but rather denotes the presence ofat least one of the referenced item.

The use of the terms “first”, “second”, and the like does not imply anyparticular order, but they are included to identify individual elements.Moreover, the use of the terms first, second, etc. does not denote anyorder of importance, but rather the terms first, second, etc. are usedto distinguish one element from another. It will be further understoodthat the terms “comprises” and/or “comprising”, or “includes” and/or“including” when used in this specification, specify the presence ofstated features, regions, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components, and/or groups thereof.

Although some features may be described with respect to individualexemplary embodiments, aspects need not be limited thereto such thatfeatures from one or more exemplary embodiments may be combinable withother features from one or more exemplary embodiments.

Referring to FIGS. 1-21, a bidirectional intravascular cannula 100 orcatheter is provided, which in certain configurations may be used inperipheral ECLS, such as extracorporeal membrane oxygenation (ECMO) orcardiopulmonary bypass to provide and return blood bidirectionally to apatient's blood vessel. In an exemplary embodiment, the cannula 100 is asingle cannula that is configured to provide bidirectional blood flowusing a reverse flow port 110. For example, the cannula 100 can beinserted into a patient's blood vessel to provide blood in a firstdirection from a distal end 124 of the cannula 100, such as toward thepatient's heart, and in a second direction (preferably opposite to thefirst direction) from a reverse flow port 110, such as to flow towardthe distal portion of the patient's limb in which cannula 100 has beenplaced. Thus, the bidirectional intravascular cannula 100 reduces orobviates the need for a second cannula, such as a currently availableunidirectional cannula used in veno-arterial ECLS procedures, to beplaced in a second or opposite direction of flow. As discussed below,the cannula 100 is further configured to be inserted into the patient atan insertion location while reducing damage to tissue adjacent to theinsertion location, compared to typical cannula. The cannula 100 isstill further configured to remain stably positioned in the patient atthe insertion location of the patient when perturbed, such as when thepatient moves or when a line coupled to the cannula 100 is perturbed.This bidirectional intravascular cannula 100 provides bidirectionalblood flow via reverse flow port 110 and forward flow port 112 at thedistal end 124 of cannula 100, as further discussed below, which arebiocompatible.

With particular reference to FIGS. 1, 2, 5, 7 and 8, cannula 100according to certain aspects of an embodiment includes a cannula lumen114 extending through cannula 100 from a proximal end 122 to a distalend 124 of cannula 100, a forward flow port 112 at distal end 124 ofcannula 100, a reverse flow port 110 positioned proximally from distalend 124 of cannula 100 and extending through a sidewall of cannula 100from an exterior of cannula 100 into lumen 114, a cap 116 on theexterior wall of cannula 100 extending over most or all of reverse flowport 110, and a coupling 118 adjacent the proximal end 122 of cannula100. The lumen 114 of cannula 100 is a generally arcuate lumen having aproximal end that coincides with the proximal end 122 of cannula 100,and a distal end that coincides with distal end 124 of cannula 100, andis configured to fluidly and percutaneously communicate blood from aninlet portion 126 of cannula 100 to an outlet portion 128 of cannula100. For example, in one embodiment the inlet portion 126 is integrallyformed with coupling 118 at the proximal end 122 of cannula 100, and theoutlet portion 128 includes the reverse flow port 110 and the forwardflow port 112 near the distal end 124 of the cannula 100. Coupling 118is configured to couple and operate with typical ECLS tubing andequipment (not shown). The cannula lumen 114 of the current embodimentcan be various diameters, similar to typical cannulas, such as 12-25French, although other diameters may be employed for particularsituations as desired by an operator without departing from the spiritand scope of the invention.

In a particular embodiment, the general arcuate cannula lumen 114 doesnot have a particularly fixed angle between the proximal end 122 anddistal end 124 of cannula 100. For example, the general arcuate cannulalumen 114 can have an angle between the proximal end 122 and distal end124 of approximately 15 degrees, or between 5 degrees and 180 degrees.

Cannula 100 is preferably formed of a biocompatible material, such as ametal (e.g., alloy, stainless steel, titanium, etc.), plastic (e.g.,PEEK, PMMA, Nylon, Polyurethane, etc.), ceramic, composite, or the like.In an exemplary embodiment, cannula 100 is formed as one piece ofmaterial; however, cannula 100 may alternatively be formed of multiplepieces of material (e.g., the cannula 100 is formed as one component andthe coupling 118 and/or cap 116 are formed as another component that areattached to the cannula 100 component). Furthermore, cannula 100 can beformed according to many typical manufacturing methods, such as dipping,machining, injection molding, lay-ups, additive manufacturing methods,and the like. Still further, cannula 100 may include a biocompatiblecoating (such as polyethylene or the like) to protect cannula 100,reduce friction, or improve flow. In certain configurations, cannula 100may include structural reinforcement to increase the strength andrigidity of the cannula 100, as shown in FIG. 2. By way of non-limitingexample, such structural reinforcement may comprise a thin reinforcementwire 138, which is generally covered by a coating (such as thebiocompatible coating discussed above) to provide a smooth surface.

Next, and with reference to FIGS. 1, 3, and 4, reverse flow port 110 isconfigured to provide blood flow in a different and preferably reversedirection relative to blood flow within the cannula lumen 114 and fromthe forward flow port 112. For example, FIGS. 3 and 4 show the cannula100 providing for blood flowing through the cannula lumen 114 from theproximal end 122 of cannula 100 to the forward flow port 112, and thereverse flow port 110 configured to provide blood flow from the cannulalumen 114 into the blood vessel away from the forward flow port 112(i.e., away from the distal end 124 of cannula 100). In a particularlypreferred embodiment, and as shown in FIG. 9, a distal end of reverseflow port 110 is positioned 5 cm from the distal end 124 of cannula 100so as to ensure adequate flow in both directions without excessiveturbulence or other interference between the flows. As discussed ingreater detail below, the outer surface of cap 116 over reverse flowport 110 is further configured to reduce damage (e.g., compared to atypical ECLS cannula) to the patient's tissue (e.g., skin, muscle, andblood vessels) when placing, inserting, or removing the cannula 100. Inan embodiment, cannula 100 is placed into a patient's blood vesselaccording to typical methods and guidelines. Also as discussed ingreater detail below, cap 116 over reverse flow port 110 is stillfurther configured to reduce the likelihood that the cannula 100 willinadvertently displace from the patient, for example, when cannula 100is perturbed or the patient moves, and also reduce damage to thepatient's tissue if cannula 100 is perturbed or inadvertently displacedfrom the patient, compared to a typical cannula.

In an embodiment, reverse flow port 110 includes an aperture 130 or hole(see FIGS. 4, 5, 9, 13, 14, and 17-19) extending through the wall ofcannula 100 from lumen 114 to the exterior of cannula 100. The aperture130 is configured to fluidly communicate blood flow from the cannulalumen 114 to the patient's blood vessel. More particularly, a portion ofblood flowing through lumen 114 toward distal end 124 of cannula 100will escape through aperture 130 before it reaches distal end 124 ofcannula 100. The interior of cap 116 is configured to generally directblood flow that escapes from lumen 114 through aperture 130 in a desireddirection, such as a direction opposite to the direction of blood flowfrom the forward flow port 112, while the exterior of cap 116 isconfigured to reduce the likelihood of damage to the patient's tissue,as described herein. The combination of the cap 116 configured asdescribed herein and aperture 130 fluidly communicate blood flow fromthe cannula lumen 114 to the patient's blood vessel, as described above,while providing preferential blood flow properties, such as desiredblood flow velocity and reducing turbulence. Furthermore, in aparticular embodiment and as discussed above, the reverse flow port 110and the forward flow port 112 are spaced relative to each other alongthe cannula lumen 114, such as by a distance of 5 cm, to reduce thelikelihood of damage, etc., as described above (see, e.g., FIG. 2). Forexample, the reverse flow port 110 can be displaced approximately 5 cmfrom the forward flow port 112. The reverse flow port 110 can bedisplaced approximately 5 cm forward of the insertion point of thecannula 100 into the patient's blood vessel. As a further example, thereverse flow port 110 is displaced distal of an arcuate portion of thecannula 100, such as positioned on a straight portion of the cannula100.

With continuing reference to FIGS. 1A, 4-6, and 9-16, and in accordancewith certain aspects of an embodiment, cap 116 is on the exterior ofcannula 100 and generally covers aperture 130. The exterior of cap 116generally has a convex, parabolic, and ramp-like shape, such that thecap 116 fluidly communicates blood flow in one direction only. However,in alternative embodiments, the cap 116 can be configured to communicateblood flow in a plurality of directions. As shown in the top views ofcap 116 of FIGS. 5 and 6, and in accordance with certain aspects of anembodiment, cap 116 generally has a parabola-like outline, such that itis formed by a body portion 132 that has a ramp-like shape thatintersects a bottom portion 120 of the exterior of cannula 100, and aleg portion 134 (e.g., having two leg-like shapes 134 a and 134 b) thatgenerally intersects with side portions 136 of the exterior of cannula100 (see FIGS. 5, 6, 6B, and 6C). Body portion 132 of cap 116 isgenerally convex to direct blood flow in a desired direction whilereducing the likelihood of inducing turbulence. In an embodiment, theexterior of the body portion 132 of the cap 116 is generally configuredto rest on an inner wall of a patient's blood vessel, such that theinner wall of the blood vessel does not substantially interfere withblood flow between aperture 130 and the blood vessel. As best seen inFIG. 1A, the exterior surface of cap 116 is configured to contact anddisplace the inner wall of the blood vessel so as to optimally positionaperture 130 with respect to the inner wall of the blood vessel. In aparticular embodiment, in order to achieve such optimal positioning ofaperture 130 with respect to the inner wall of the patient's bloodvessel to provide optimal flow characteristics, and with reference toFIG. 12, cap 116 may have a height (from the exterior of cannula 100 tothe interior face of cap 116) of, for example, between 0.5 mm and 3 mm,and more preferably between 0.8 mm and 2 mm, and most preferably 1 mm,with the wall of cap 116 having a thickness of preferably between 0.05mm and 2 mm, and more preferably of 0.2 mm, and a maximum width at aproximal end of cap 116 of preferably 4 mm. Furthermore, the roundednature of the body portion 132 and leg portion 134 provides cap 116 ashape that is configured to slide on the patient's tissue withoutentangling or snaring the patient's tissue to reduce the likelihood ofdamage to the patient's tissue when placing the cannula 100 in thepatient and when removing the cannula 100 from the patient (e.g.,desired or inadvertent), as described above, such that cap 116 has nosubstantially sharp, abrupt, or barb-like surfaces.

Further, body portion 132 and leg portion 134 of cap 116, in accordancewith further aspects of an embodiment, are configured to achieve thedesired flow properties. The body portion 132 generally forms theparabola-like outline of the cap 116, and extends from the cannula lumen114 to the leg portion 134 at a ramp angle. The ramp angle (“A” of FIG.11) of body portion 132 of cap 116 reduces the likelihood of damage tothe patient's tissue during insertion by providing a substantiallysmooth surface, as discussed above. Likewise, the ramp angle (“B” ofFIG. 11) of leg portion 134 of cap 116 reduces the likelihood of damageto the patient's tissue during removal, with both body portion 132 andleg portion 134 having no substantially sharp, abrupt, or barb-likesurfaces. In a particular embodiment, the ramp angle A of body portion132 is preferably in the range of 10 degrees to 70 degrees, and morepreferably in the range of 15 degrees to 22 degrees. Likewise in aparticular embodiment, the ramp angle B of leg portion is preferably inthe range of 10 degrees to 70 degrees, and more preferably 20 degrees.Leg portion 134 includes two elongated leg-like features 134 a and 134 bthat each extend from the body portion 132 on the bottom portion 120 ofcannula 100 to the side portions 136 of cannula 100. Thus, cap 116 isparticularly configured to reduce the likelihood of cross-flow (e.g.,blood flow in the blood vessel between the reverse flow port 110 and theforward flow port 112) by reducing the likelihood of blood flow aroundthe leg portion 134. The leg portion 134 is generally angled from theside portions 136 of the cannula lumen 114 to the body portion 132, suchthat the leg portion 134 generally has an arcuate and concave outline(best viewed in FIG. 1A). The angle of the leg portion 134 may varyaccording to various properties of the cannula 100, such as the cannulalumen diameter, the desired blood flow properties (e.g., direction,velocity, turbulence), and placement location. Furthermore, the angle ofthe leg portion 134 and concave outline may be selected to reduce thelikelihood of damage to the patient's tissue by providing a smoothsurface, as discussed above, such as having no substantially sharp,abrupt, or barb-like surfaces. In an alternative embodiment, theleg-like features 134 a and 134 b may have unequal angles and/or arcuateshapes.

Aperture 130 is configured to fluidly communicate blood flow from thecannula lumen 114 to the patient's blood vessel. In a particularembodiment, aperture 130 of the current embodiment has a parabola-likeopening similar to the parabola-like outline of the cap 116, as shown inFIGS. 5 and 14, in which the vertex of the parabola is located at thedistal-most portion of aperture 130 (closest to forward flow port 112).However, aperture 130 may have a different opening size or shapecompared to the cap 116. In a particular embodiment, aperture 130 has anopening size that is generally similar to the diameter of the cannulalumen 114, such as 12-23 French. For example, FIG. 5 shows a top view ofcap 116 (shaded) and aperture 130 (dashed line) that do not strictlyoverlap, but have a generally similar outline. In a particularembodiment and as shown in FIG. 18, the aperture 130 has an opening thatis approximately 4 mm wide and approximately 7 mm long. Alternatively,aperture 130 may have an ellipsoidal-like opening as shown in FIG. 4.

Now referring to FIGS, 1-3, 7-9, and 19, forward flow port 112 isconfigured to fluidly communicate blood from the cannula lumen 114 intothe patient's blood vessel in a proximal direction (e.g., towards theheart and other arteries). In accordance with a particular embodiment,forward flow port 112 has a cross-sectional opening that is similar tothe cross-section of cannula 100, while reverse flow port 110 isconfigured to communicate blood flow from the cannula lumen 114 into theblood vessel away from the forward flow port 112 (e.g., away from thedistal end 124 of cannula 100). In other configurations, forward flowport 112 may include a plurality of apertures or fenestrations.

Coupling 118 adjacent proximal end 122 of cannula 100 may be configuredto attach to standard medical equipment, such as ECLS devices or anydevice for circulating blood through a major blood vessel having bloodflow in an opposing direction, such as cardiac bypass, mechanicalarterial support, venous access device (VAD) support, or the like.

Next, and with reference to FIGS. 20 and 21, an obdurator 200 may beprovided for use with cannula 100 for placement of cannula 100 within apatient's blood vessel. Obdurator 200 is a solid member having anoutside diameter approximately the same as the inside diameter ofcannula lumen 114 at the distal end 124 of cannula 100, and issufficiently long so that the distal end 202 of obdurator 200, wheninserted in cannula 100, extends beyond the distal end 124 ofcannula100. In use, access may be gained to the vessel (such as bymaking an incision) and the obdurator 200 is inserted into cannula 100,with distal end 202 of obdurator 200 extending beyond the distal end 124of cannula 100. Obdurator 200 then pushes through the patient's softtissue and into the patient's blood vessel, gaining entrance for cannula200. Once inserted in place, obdurator 200 is removed, leaving cannula100 in place in the patient's blood vessel.

Obdurator 200 is particularly configured to enable an operator to knowwhen reverse flow port 110 is positioned within the patient's bloodvessel. More particularly, obdurator 200 includes a concave channel 204extending into the surface of obdurator 200. Concave channel has adistal end closest to distal end 124 of lumen 114 that, when obdurator200 is fully inserted into cannula 100, aligns with or is distal toreverse flow port 110 (as show in FIG. 20). Channel 204 allows blood toflow in cannula 100 when obdurator 200 is in place within cannula 100,with such blood flowing from the patient's blood vessel into reverseflow port 110, into channel 204, and proximally through channel 204(toward the proximal end 122 of cannula 100) into a widened section 138of cannula 100 and ultimately toward preferably a luer locked hole (notshown) positioned near proximal end of cannula 100, such as on coupling118. With obdurator 200 completely inserted into cannula 100, the distalend of concave channel 204 aligns with reverse flow port 110. As reverseflow port 110 enters the patient's blood vessel, arterial pressure willpush blood through reverse flow port 110, into concave channel 204 inobdurator 200, and fill the empty lumen 114 of cannula 100 to finallyexit out of the luer locked hole near the proximal end 122 of cannula100. In a particular configuration, concave channel 204 has a depth intothe surface of obdurator 200 and a width that is 5-30% of the diameterof obdurator 200.

Disclosed above is a bidirectional intravascular cannula, or catheter,that is configured to provide and return blood bidirectionally. Thebidirectional intravascular cannula reduces or obviates the need for asecond cannula to be placed in a second or opposite direction of flow ofcurrently available unidirectional cannulae. The cannula is furtherconfigured to be inserted into the patient at an insertion locationwhile reducing damage to tissue, compared to typical cannula, which isadjacent to that insertion location. This bidirectional intravascularcannula provides bidirectional flow via a biocompatible, reverse flowport. The cannula is further configured to stably remain in the patientat the insertion location of the patient when perturbed, such as whenthe patient moves slightly or when a line coupled to the cannula isperturbed. This bidirectional intravascular cannula providesbidirectional flow via a reverse flow port and the forward flow port,which are biocompatible.

While the exemplary embodiments have been shown and described, it willbe understood by those skilled in the art that various changes in formand details may be made thereto without departing from the spirit andscope of the present disclosure as defined by the appended claims.

In addition, many modifications can be made to adapt a particularsituation or material to the teachings of the present disclosure withoutdeparting from the essential scope thereof Therefore, it is intendedthat the present disclosure not be limited to the particular exemplaryembodiments disclosed as the best mode contemplated for carrying out thepresent disclosure, but that the present disclosure will include allembodiments falling within the scope of the appended claims.

What is claimed is:
 1. A bidirectional flow catheter system, comprising:a cannula having a distal end and a proximal end opposite said distalend; a forward flow port at said distal end of the cannula, said forwardflow port configured to direct fluid from said cannula in a firstdirection; a reverse flow port positioned proximally from said distalend of said cannula, said reverse flow port configured to direct fluidfrom said cannula in a second direction; and a cap positioned on anexterior of said cannula and extending over said reverse flow port.